Simultaneous multiple twisting apparatus

ABSTRACT

In each twisting unit of a multiple twisting apparatus, a twofor-one twisting assembly imparts a first twist to each component yarn while a ring twisting assembly imparts a second twist to a doubled first-twisted yarns. A plurality of first twisted yarns are doubled under tension control and the doubled yarn is taken up by a feed mechanism so as to be supplied to the ring twisting assembly under tension control via a yarn passage formed behind the two-for-one twisting assemblies. The two-for-one twisting assemblies are arranged in two alignments along a lengthwise direction of the apparatus. All driving members are driven synchronously at a starting period and at a time of stopping the twisting operation.

United States Patent 11 1 Matsumura et al.

[ Nov. 12, 1974 [54] SIMULTANEOUS MULTIPLE TWISTING 3,146,572 9/1964 Ke ser 57/92 X APPARATUS 1224.945 3/l96l Vibbcr 57/101 x ['15] Inventors: sakujiro Matsumura; Tadashi FOREIGN PATENTS OR APPLICATIONS Yamamura; Akira Ogura: Masataka 1,027,270 5/1953 France 57/5855 Hayashi, all of Aichi-ken,' Japan 404.168 3/l933 Great Britain 57/58.?46

[73] Asslgneez :J'fipgg Company Lmmed Primary E.ram1'nerDonald E. Watkins [22] Filed: May 21, 1973 57 ABSTRACT PP 362,107 In each twisting unit of a multiple twisting apparatus, 9 a two-for-onc twisting assembly imparts a first twist to each component yarn. while a ring twisting assembly [30] Foreign Application Pnomy Data im arts a second twist to a doubled first-twisted yarns.

M 26 197' J 47 05l680 p 7 A plurality of first twisted yarns are doubled under tension control and the doubled yarn is taken up by a [52] Cl 8 7 ig 25 6 feed mechanism so as to be supplied to the ring twisting assembly under tension control via a yam passage 25 f 'l 'f Dolh 1/10 Dolh 1/28 Dolh 7/86 formed behind the two-for-onc twisting assemblies. ;glsg gg g ''g i g gggg 2 :6 25? The two-for-one twisting assemblies are arranged in 7 two alignments along a lengthwise direction of the ap- 8( 90, 104, I06, 34 R, 55.5 i [56] References Cited All driving members are driven synchronously at a UNITED STATES PATENTS starting period and at a time of stopping the twisting 1 o eration. 2.576936 12 1951 Heffelfinger 57 20 p 2.979.882 4/1961 Bromley et al. 57/5854 x 10 C 6 Drawlng gu I/P. 17 l i 26 4 1 26 68 M 17 19 4 I. 69 b9 1 I l b 8 7 l l0 4 6 61 5 A,

5 28 e4 62 59 4 59 O 55 53 29 56 54 2 17 49 7 7 11 48 2 5 45 1 29 H 12 1o 46 32 38 9 12 54 39 46 47 10 g 35 52 Pmminwnv 12 \914 1846365 SHEEF 2 BF 5 SIMULTANEOUS MULTIPLE TWIST ING APPARATUS SUMMARY OF THE INVENTION The present invention relates to an improved multiple twister, more particularly relates to an improvement of a multiple twisting apparatus wherein a first twist is applied to each component yarn by a two-forone twisting assembly while a second twist is applied to a strand of combined first-twisted component yarn by a ring twisting assembly. All driving members are ponent yarns by a pair of twofor-one twisting assemblies, respectively, and thereafter a second twist is imparted to a strand of combined yarns in one continuous process. According to our experience, in the first mentioned twisting assembly, it is very difficult to control the balance of tension between component twisted yarns, and consequently, it is impossible to prevent yarn breaks of component yarns during the operation. The larger size of a yarn package mounted on an inside spindle of the assembly is used the, more pronounced the abovementioned problems become. Therefore, there is-a certain limitation in the size of a full packaged'bobbin mounted on the inside spindle of the assembly. As doffing of the exhaust bobbins from the inside spindle and donning of the full packaged fresh bobbins on the inside spindle is often required, if the size of the abovementioned full packaged bobbin is restricted, the productivity of the twisting assembly is also restricted.

The second of the above-mentioned apparatus is utilizedfor processing orientable continuous filament yarn. This apparatus comprises, incombination, means for withdrawing the orientable yarn from a yarn packageand for twisting thesame so as to produce two twists for each revolution of a shaft, a first yarn fowwarding device associatedwith the withdrawing and twisitng means to draw the yarn at a speedgreater thanthe speed at which the yarn is withdrawn from the yarn package whereby the yarn is twisted and stretched simulta neously, and means for taking up the thus-processed yarn inan ordinary manner. In this apparatus, a yam-with--drawing deviceis disposedin a yarn passage formedin a hollow axis of the yarn package, and this deviceis drivenin a controlled rotational relationship withthe first yarn forwardingdevice. As described in the specification of thisprior patent, when a first twist is impartedto a yarn by the two-for-one twisting assembly, a yarn takenfromthe package is positively carried by a plurality of rollers so as to lead toward a rear side direction of the assembly and afterpassing througha hollow shaft of a worm gear and a yarn guide, the yarn is carried toa front position of the assembly, andthen two processed yarns are doubled. thh doubled yarnis stretched while passing through a stretching device,

and finally, a second twist is imparted to this stretched yarn by a ring twisting assembly.

Based on our experience, we have found that. in the yarn processing operation using the second of the above-mentioned apparatus, as the orient able yarns are firstly provided with a first twist, respectively, and next the double yarn is subjected to the stretching operation and, finally, the second twist is imparted to the stretched yarn, it is not easy to maintain the twist configurations of component yarns in a balanced condition before doubling. If an unbalanced condition is created,

this unbalanced twist configuration between the component yarns creates an undesirable configuration of the second twist, such as the creation of snail. The stretching operation enhances the above-mentioned objectionable features. According to our experience, if a twisted double yarn is subjected to a stretching operation, the twist (second twist) tendsto displace toward an upstream portion of the yarn which is being carried through the yarn passage in the stretching zone. In otherwords, the first twisted yarn is mainly stretched in a doubled condition without twists. However, when the twists are concentrated in the above-mentioned upstream portion and the concentrated twists reach a saturated condition, the concentrated twists are displaced to a downstream portion of the yarnwhich is being carried through the yarn passage in the stretching zone. And when the number of twists remaining in the yarn, which is being carried through the yarn passage, islowered to a certain limit, the above-mentioned concentration of the twists in the upstream portion of the yarn commences. The above-mentioned displacement and concentration of the twists is repeated during the operation. According to the above-mentioned displacement and concentration of the twists, the stretching of the doubled yarn cannot be carried out uniformly and, further, the distribution of twists of each component yarn becomes irregular. Consequently, it is very difficult to produce a multiple twisted yarn having uniform quality. In other words, the second-mentioned apparatus can not be utilized for producing a tire-cord yarn for vehicle tires which requires a high uniformity of twist configuration and mechanical property. However, this apparatus may be utilized to produce a tire-cord yarn for manufacturing a conveyer belt which is preferably utilized for carrying substances of light weight because there is no danger of serious accidents causing injury to human beings as would be the case if'this tire-cord yarn were to be used in vehicle tires.

It may be considered that the second mentioned apparatus can be utilized for producing multiple twisted yarn by omitting the stretching means. However, in this apparatus, it is difficult to maintain a balanced condition between the first twists imparted to each component yarn because of the uneven condition of the ballooning which is inevitable in the two-for-one twisting assembly of this apparatus.

The principal object of the present invention is to eliminate the above-mentioned drawbacks of the conventional apparatus by presenting a multiple twisting A further object of the present invention is to provude a multiple twisting apparatus having superior operative functions such as a particular function being capable of preventing the creation of slackened yarn or preventing instant elevation of yarn tension at the time of doffing full packaged bobbins from the second twisting assemblies or donning full packaged bobbins on to the first twisting assemblies or starting the twisting operation-after-temporarily stopping the operation.

Still another object of the present invention is to provide a compact multiple twisting apparatus which will then reduce the required installation space.

A still further object of the present invention is to provide a multiple twisting apparatus which is easily handled so that the operation cost can be reduced.

In the multiple twisting apparatus according to the present invention, at least one of the twisting units, each comprising at least-a pair of two-for-one twisting assemblies as a first twisting device and a ring twisting assembly as a second twisting device, is mounted on the apparatus in a lengthwise direction. In each twisting unit, a plurality of the twisted component yarns are combined or doubled into a double yarn and the doubled yarn is imparted a second twist by the ring twisting assembly.

It is the characteristic features of the present invention that, in each twisting unit, a plurality of two-foronetwisting assemblies, which are substantially in an upright disposition, are arranged in a side by side relationship in a row substantially perpendicular to the lengthwise direction of the twisting apparatus, and each of the twisted component yarns are combined under balanced tension, and thereafter the doubled yarns are carried along a yarn passage formed behind the first twisting two-for-one twisting bya plurality of guide members and fed to the second twisting device. Further, in the present invention, the first twisting devices are synchronously driven with the'second twisting device at the period of commencing the twisting operation and at a time of stopping the operation. To carry out the twisting operation under stable conditions, it is essential to control the yarn tension in each twisting device. Therefore, in the present invention, each first twisting device is provided with a tension control mechanism, and the tensions of the twisted component yarns taken from the respective yarn packages are controlled before doubling and, in addition, the yarn tension of the doubled yarn is also controlled. These tensions are required to satisfy a particular relation T, T T where T,, T and T represent the yarn tension controlled by the above-mentioned tension controls, respectively. That is, T represents a yarn tension in the first twisting device, T a yarn tension just before doubling and T a yarn tension of one of the doubled yarns. According to the above-mentioned particular idea of the arrangement of the first twisting device yarn passage, a synchronous driving mechanism and tension control, the purpose of the present invention can be satisfactorily attained.

Further features and advantages of the present invention will be apparent from the ensuing description with reference to the accompanying drawings to which the scope of the invention is in no way limited.

BRIEF EXPLANATION OF THE DRAWINGS FIG. 1 is a partial perspective view of an embodiment of the multiple twisting apparatus. according to the present invention,

FIG. 2 is a schematic perspective view of a unit of the twisting assembly shown in FIG. 1,

FIGS. 3 and 4 are a perspective view and a side view respectively, of another embodiment having a special tension control mechanism according to the present invention,

FIGS. 5 and 6 are a plan view and a side view respectively, of a synchronous driving mechanism applied to the first twisting device according to the present invention.

DETAILED EXPLANATION OF THE INVENTION Referring to FIGS. 1 and 2 in an embodiment of the multiple twisting apparatus according to the present invention, a plurality of twisting units are arranged along the lengthwise direction of the apparatus and at both sides thereof. Each twisting unit comprising a first twisting device 1 and a second twisting device 2 disposed below the first twisting device 1. The first twisting'device 1 comprises a pair of two-for-one twisting assemblies 1a and 1b, the second twisting device 2 comprises a ring twisting assembly 20, and the first twisting device 1 and second twisting device 2 are synchronously driven by a synchronous driving mechanism which will be hereinafter explained in detail. The twofor-one twisting assembly is utilized as one component of the twisting assemblies of a first twisting device. Each two-for-one twisting assembly la, or lb is provided with a housing or balloon guide bucket 4 and a spindle 5 which is driven by an endless belt 7 and a rotating disc 8. In each ring twisting assembly 2a utilized as a second twisting device 2, a bobbin 11 is mounted on a spindle 10 which is driven by an endless belt 12. The twofor-one twisting assemblies la, 1b are arranged in a side-by-side relation and their spindles 5 are rotatably supported by a pair of bearings 13 in an up right condition. The bearings 13 are rigidly mounted on a top spindle rail 14 in such a way that they are aligned along a line which is substantially perpendicular to a lengthwise direction of the top spindle rail 14. As shown in FIG. 1, a plurality of twisting units are arranged on both sides of the multiple twisting apparatus along the lengthwise direction thereof. As the first twisting device of each unit comprises a pair of two-forone twisting assemblies 1a, lb arranged as mentioned above, in each side of the multiple twisting apparatus shown in FIG. 1, there are two alignments of two-forone twisting assemblies; that is, in a twisting unit, a twofor-one twisting assembly la is located on a front side alignment and the other two-for-one twisting assembly 1b is located on a rear side alignment facing the abovementioned two-for-one twisting assembly la of the front side alignment, and a second twisting device 2 disposed below the above-mentioned first twisting device 1.

According to our experience, if it is required to produce a multiply yarn consisting of more than two component yarns, a required number of the abovementioned two-for-one twisting assemblies disposed in an adjacent condition can be used as a group for doubling the required number of first twisted yarns. In this alignment are referred to as a back assembly. It is pref:

erable for the sake of easy manual doffing and donning of packages, to arrange each spindle 5 of the first twisting assembly in a forward inclined condition at an angle within the range of 45.

In this embodiment, the bearing 13 is aligned along a line which is perpendicular to the lengthwise direction of the top spindle rail 14. However, it is also practical to dispose the bearing 13 along a line which is a little inclined from a line perpendicular to the lengthwise direction of the top spindle rail 14.

In th two-for-one twisting assembly 1a, 1b a yarn is withdrawn from the package 15 mounted on the spindle 5 and led into a yarn passage formed in the spindle 5 by way of a top aperture 6 ofthe spindle 5 and delivered from an outlet aperture 9 formed on the rotating disc 8 and taken up toward a yarn guide 17.

The yarn passing through a yarn passage a between the outlet aperture 9 and the yarn guide 17 has a tendency to made a balloon about the housing 4. To control this balloon, a pair of balloon control rings 16 are mounted-on the two-for-one twisting assembly 1. When the yarn is carried through the yarn passage formed inside the spindle 5, the yarn tension is controlled by a conventional tension control means as shown in FIG. 3. This controlled yarn tension is hereinafter referred to as a tension T and the yarn tension in the yarn passage a is hereinafter referred to as a tension T As it is well known from many prior art patents, such as British Pat. No. 896,493, a first twist is imparted to a yarn taken from a package until the yarn arrives at theyarn guide 17. Duplicate twists are imparted to the yarn withdrawn from the package 15 at each one revolution of the spindle 5.

The first twisted yarns 18a, 18b are then doubled by a thread guide 19 and a strand or doubled yarn 20 is carried to the second twisting device 2 that is the ring stream position tothethread guide 17. The detailed mechanism of this control device is hereinafter explained with reference to the drawings of FIGS. 3 and 4.

According to our practical tests of the process, certain unbalanced conditions in yarn tension were observed when the doffing, donning operations are carried out in the first and second twisting devices 1 and 2. Consequently, in the present invention, a reserve mechanism for controlling the yarn tension is disposed along a yarn passage'between'the thread guide 19 and 26. This reserve mechanism comprises a pair of guide rollers 21 and which are rotatably supported at stationary positions by brackets (not shown) and an intermediate guide roller 24 which is rotatably supported by a supporting member 22. The supporting member 22 is I always pulled upward by a tension spring 23 secured at one end to a machine frame (not shown). As the supporting member 22- is capable of being displaced'upward by the pulling force of the tension spring 23 and the doubled yarn 20 passes the guide rollers 21', 24 and 25 as shown in FIG. 2, if the tension of the doubled I yarn 20 is lowered, in other words, if the doubled yarn 20 becomes slack, the guide roller 24 is displaced upward, so that the slack portion of the doubled yarn 20 is reserved'in the mechanism, and if the tension of the doubled yarn 20 is increased, the guide roller 24 is pulled downward so that the tension can be compensated. The above-mentioned controlled tension ofthe doubled yarn 20 is hereinafter referred to as tension T According to our practice processing test, it is very important tomaintain the balanced condition between sirably as follows: T, is controlled within the range of twisting assembly 2a, by way of a yarn passage b formed behind the back two-for-one twisting assembly 1. This yarn passage b is defined by a thread guide 26, and a bottom thread guide 27. The doubled yarn 20-is then taken up by a feed mechanism comprising a pair of bottom rollers 28, which are positively driven, and a top roller 29 rotatably mounted on the bottom rollers 28. The feed mechanism is mounted on a horizontal machine frame 3. The doubled yarn 20 delivered from the feed mechanism is then wound on a bobbin 11 while imparting the second twist by this ring twisting assembly 2a. in FIG. 2, a ring and a traveller are represented by reference numerals 30 and 31, respectively. In this embodiment, each spingle 10 of the ring twisting assembly 2a is rotatably supported by a spindle bolster 32 which is mounted on a bottom spindle rail 33 at a position corresponding to the first twisting device 1 of the unit. The ring 30 is also rigidly mounted on a conventional ring rail 34.

In the above-mentioned embodiment, it is very important to maintain a balanced condition between the yarn tensions T of two component yarns supplied from the front back two-for-one twisting assemblies 1a, lb. To attain this purpose, a tension control device is disposed along the yarn passages at an adjacently up- 0.005 g/denier to 0.050 g/denier; T is controlled within the range of 0.035 g/denier to 0.150 g/denier, and; T is controlled within the range of 0.070 g/denier to 0.200 g/denier. The tensions Ti, Band T however,

have a relationship of: T is larger than T,, and T islarger than T that is, T T T Particularly, T is defined in a range of from 2 to 10 times T and T is defined in a range from 1.1 to 4 times T For the purpose of establishing better operating conditions, it is desirable to apply a tension control mechanism by which the above-mentioned yarn tensions can be controlled as follows. If the starting and stopping of the first twisting device are operated synchronously with the second twisting device,

K represents a frictional force of the yarn with yarn guides 83, 19 which are shown in FIG. 3; R represents a force creating a torsion kinky thread in a yarn passage between an aperture 9 and the guide 83. Otherwise, yarn in any portion of the. yarn passage from the package 15 to the feeding mechanism tends to slacken and, consequently, it becomes impossible to impart a balanced twist to the component yarns.

The tension control means for controlling the yarn tension T is hereinafter explained in detail. Referring to FIGS. 3 snd 4, the tension T is controlled by a ten sion spring. An intermediate yarn guide 83 is secured to a bracket 84. The tension control mechanism'for controlling the yarn tension T comprises a pair of feelers 74, 77 supported by pins 72, 73, respectively. These pins 72, 73 are tumably mounted ona bracket 94. The fceler 74 is provided with a free end portion 740 curved so as to cross a yarn passage between the yarn guide 17 and the yarn guide 83. An additional rod 76 provided with a free horizontal end portion 76a is secured to the pin 73. The feeler 77 is provided with a similar free end portion 770 which crosses another yarn passage between another yarn guide 17 and 83. An additional rod 78 provided with a free horizontal end portion 78:: is secured to the, pin 72. A horizontal supporting plate 86 is projected from the bracket 94 and a spring holder 87 is secured to the bracket 94. The thread guide 19 is also secured to the bracket 94. A tension spring 84 connects the horizontal end portion 78a of the rod 78 and the spring holder 87, while another tension spring 85 connects the horizontal end portion 76a of the rod 76. Consequently, the feelers 74, 77 are always provided with turning forces so as to displace their free end portions 74a, 77a upwards. In other words, the yarn tension T of the first twisted yarn 18a, or 18b can be maintained in a balanced condition by the pulling force created by the respective tension spring 84, 85. The first twisted yarns 18a, 18b are carried to the thread guide 19 so as to double them and the double yarn 20 is carried to the thread guide 26 (FIG. 2).

In this embodiment, a modified yarn reserve mechanism is utilized instead of the mechanism shown in FIG.

2, and a so-called, cantilever principle is applied. In the yarn reserve mechanism shown in FIGS. 3 and 4, a cantilever type rod 90 is secured to a turnable pin 89 which is tumably mounted to the bracket 94. A counter weight 91 is adjustably mounted on a free end portion of the rod 90 while another free end portion thereof is formed as a curved portion 92 which crosses the yarn passage between the thread guide 19 and 26. A horizontal bar 88 is secured to the bracket 94 in such a way that the doubled yarn 20 passes proximately below the bar 88. Therefore, by fixing the counter weight 91 at a suitable position on the rod 90 the curved portion 92 of the rod 90 urges the doubled yarn 20 upward so that the tension T;, can be maintained in a balanced condition by the turning force of the rod 90 about the pin 89. And, even if the doubled yarn 20 is slackened by a stop of the twisting operation, the slackened yarn portion can be reserved in the passage between the thread guides 19 and 26 by forming a reserved loop between the horizontal bar 88 and the thread guide 19 while maintaining desirable yarn tensions T and T In this embodiment, the above-mentioned feelers 74, 77 can be used as a means for detecting yarn breaks and stopping the operation of the twisting assembly. Referring to FIGS. 3 and 4, a limit switch 79 is mounted on the bracket-94 in such a way that a detecting rod 93 of the limit switch 79 is positioned above the horizontal end portions 76a and 78a of the rods 76, and 78. Therefore, when one of first twisted yarns 18a, 18b is broken, one of feelers 74, 77 is turned, and then one of horizontal end portions 76a, 78a, urges the rod 93 upward. According to the abovementioned motion, the limit switch 79 is actuated so as to stop the driving of the apparatus. As thestop mechanism which is actuated by a limit switch is well known in the art, the explanation of the detailed mechanism of the stop means is omitted here. However, in this embodiment, if it is necessary to stop the twisting operation of a twisting unit for some reason such as piecing broken yarn ends, the yarn tension of theyarns 18a, 18b are lowered so that the feelers 74, 77 are turned and thh horizontal end portions 76a, 78a, actuate to turn the rod 93 upward. In such a condition, the twisting unit can not commence driving. To avoid such an unnecessary situation, a lever is tumably mounted on the pin 72. The lever 80 is provided with a free portion 81 extended toward the limit switch 79 in such a way that the free portion 81 extends adjacently over the horizontal end portions 76a, 78a, of the rods 76, 78 respectively. Another end of the lever 80 is capable of engaging with a rest member 82 secured to the bracket 94. When the end of the lever 80 engages with the rest member 82, the free portion 81 is positioned at a free position above the horizontal end portions 76a, 78a of the rods 76, 78, and; when it is necessary to prevent the actuation of the limit switch 79, the end of the lever 80 is disengaged from the rest member 82 and turned counterclockwise about the pin 72 so that the free end portion 81 prevents the actuation of the horizontal rods 76a, 78a against the rod 93 of the limit switch 79. 1

As already set forth, to prevent the above-mentioned undesirable condition of yarn tension, it is essential to drive the first twisting device 1 in synchronous condition with the second twisting device 2 during at least a period of starting the twisting operation and at a time utilized for stopping the twisting operation. package and the same associated with speed greater than the in an yarn-withdrawing device is disposed in formed in device is driven in with the forwarding device. this prior imparted to taken from the after passing through a to a and then the yarn is To attain the above-mentioned desirable driving condition, the endless belts 7 and endless belt 12 are driven by a common driving source as shown in FIG. 1. Referring to FIG. 1, a pulley 36 is secured to a motor shaft of a common driving motor 35.

A main shaft 39 extending lengthwisely along a machine frame is provided with a pulley 38 rigidly mounted on a free outside end portion thereof. The pulley 38 is driven by the pulley 36 by way of an endless belt 37. A pulley 50 is rigidly mounted on the shaft 39 and drives a pulley 52 rigidly mounted on a shaft 53 by way of an endless belt 51. A small gear 54 is rigidly mounted on the shaft 53. A small gear 58 mounted on a horizontal shaft 57 is driven by a gear train comprising gears 55 and 56 by meshing the gear 55 with the gear 54. Pulleys 67 are secured to the shafts 66 with are rotatably supported by respective brackets (not shown) secured to the machine frame at both sides of the machine. Each upright shaft 66 is provided with a driving pulley 67 at the top end portion thereof, while a bevel gear 65 is secured to a bottom end portion thereof. Each bevel gear 65 meshes with a bevel gear 64 rigidly mounted on a horizontal shaft 63. A pulley 60 is secured to each shaft 63. Consequently, it must be unde rstood that the two pulleys 60 are disposed at corresponding positions adjacent to the upright shafts 66 respectively. These pulleys 60 are driven by the pulley 59 by way of an endless belt 61. In this driving mechanism shown in FIG. 1, tension guide pulleys are designated by 62. At another end of the machine frame, a pair of pulleys 68 are rotatably mounted. A pair of endless belts 7 are mounted on the pairs of pulleys 67 and 68 so that each endless belt 7 is driven by the rotation of the driving pulley 67. To prevent unnecessary slip of the belt 7 on these pulleys, a plurality of tension guide rollers 69 are mounted on the machine frame as shown in FIG. 1. On the other hand, a plurality of driving pulleys 70 are rigidly mounted on the main shaft 39 at appropriate positions to drive each corresponding group of spindles 10. Each endless belt 12 is mounted on the driving pulley 70 and spindle wharves of four spindles so as to drive spindles 10. A plurality of tension guide rollers 71 are mounted on the main frame so as to prevent slippage of the endless belt l2'on these pulley 70 and spindle wharves. A main gear 40 is rigidly mounted on the shaft 39 at the gear end portion of the machine. Each pair of feeding rollers 28 are provided with small gears 49 mounted on the respective gear end portions thereof. The front side small gears 49 are driven by way of a gear treain comprising intermediate gears 41, 43 and 47 by meshing the gear 41 with the main gear 40. On the other hand, the rear side small gears 49 are driven by way of a gear train comprising intermediate gears 42, 44, 45 and 48 by meshing the gear 42 with the main gear 40. Further, the gear 45 is capable of engaging or disengaging from the gears 42 and 44, and when the gear 45 is disengaged from the gears 42 and '44, the gears 42 and '44 are able to connect directly to each-other. The other gear 46 is provided as a spare gear instead of the'gear 41 or 42. If it is required to change the direction of the first and second twist, an additional intermediate change gear (not shown) is utilized so as to transmit the driving power of the gear 54 to the gear 55 instead .of directly meshing the gear 54 with the gear 55. As the spindles 5 of the first twisting device 1, the spindles'l0 of the second twisting device 2 and thebottom rollers 28 are all driven by a common drive motor as mentioned above, the first twisting operation and second twisting operation of each twisting unit can be commencedin synchronous condition and can be stopped synchronously. Therefore, any troubles due to unbalanced yarn tension or slackeried condition of yarns can be perfectly eliminated.

The above-mentioned driving mechanism provides a very practical advantage for a manufacturing operation. This is, in case the number of the first twist and the second twist'are changed in equal ratio, the number of twists can be easily changed by changing the take up speed of the bottom rollers 28. This change of take up speed is done by changing the gears 47, 48 only. And in case the number of the first twist and the second twist are changed to a different ratio, the twist changing can be done by changing the gears 47, 48 and the gear 55. Further, as the above-mentioned driving mechanism utilizes a common drive motor 35, and the mecha nisms for driving the spindles 5 and 10 are very simple, the multiple twisitng machine can be compactly built. This is another-advantage of the present invention.

In the above-mentioned multiple twisting apparatus, a particular mechanism for disengaging the spindles 5 from the endless belt 7 is utilized. This is because, if a yarn is broken at one of the two-for-one twisting assemblies la or lb, it is necessary to stop the driving of both spindles 5 of the first twisting device 1 wherein the yarn is broken. This machanism is shown in FIGS. 5 and 6, in detail. To provide a better understanding, the mechanism for driving a multiple unit of the twisting assembly is hereinafter explained. The spindle 5a is rotatably mounted on a bearing secured to a supporting arm 96 in such a way that a spindle wharve 5a of the spindle 5a is capable of being drivenby frictional contact with the driving belt 7. Another spindle 5b is rotatably mounted on a bearing secured to another supporting arm 97 in such a way that a spindle wharve Sb is capanected to an end 96a of the arm 96 by means of a handle shaft 101. A tension spring 102 is connected to an end of the arm 97 and another end 102a of the tension spring 102 is secured to the spindle rail 14. Consequently, the spindle wharves 5a, 5b are always urged to the endless belt 7. A stop pin 103 is mounted on the handle shaft 101. A stop plate 104 is mounted on the spindle rail 14 so as to engage with the stop pin 103 when the handle ispulled toward a direction C shown in FIG. 6. When the handle is pulled toward the direction C, the supportingarms 96,97 are turned about the supporting pins 95, 98 toward the directions indicated by arrows A, shown in FIG. 6, and consequently, the contact of the spindle wharves 5a, 5b with the belt 7 is released. In other words, according to the above-mentioned motion of the handle 100, the driving of both spindles 5a, 5b can be simultaneously stopped. On the other hand, if the engagement of the stop pin 103 with the stop plate 104' isreleased, the

arms 96 and 97 are automatically'turned about their supporting pins 95, 98 toward the opposite direction to the directions represented by the arrows A, B because of the spring force created by the tension spring 102. As a result, the spindle wharves 5a, 5b are subjected to engage theendless belt 7 simultaneously. To adjust the contact pressure of the spindle wharves 5a, 5b with the endless belt 7, an adjustment member 107 which changes the length of the connecting rod 99 is mounted on the rod 99. As mentioned above, the spindles of a unit of the first twisting device 1 can be engaged or disengaged with the endless belt 7 independently from other units of first twisting devices 1, when it is necessary to piece broken yarn ends or to stop for any reason. I

To clarify the above-mentioned advantages of the multiple twisting apparatus according to the present invention, the space required for installation of the apparatus,- power consumption and comparative data of labor costs were calculated in comparison'with the conventional process. The above-mentioned comparison was done for the case of producing 840 denier two ply nylon tire cord in a production rate of 10 2/24 hr. These data are shown at the following table wherein, process A designates a process utilizing the ring twisting assemblies for imparting a first twist and second twist, process B designates a process utilizing so-called direct double twister which is explained in the starting para graph of this specification.

Conventional process Present invention Raw material Stretched nylon multifilament yarn 840 denier Cord construction 840 D/Z Number of twist 470 (Z twist) X 47.0 (S twist) T/l cm Spindle r.p.m. 6,500 5,500 6,500 3,500 7,000

Machine efficiency 95% Size of ring (diameter) in mm l0l.6 139.7 l65.l

Space 810 l,ll5 405 required for machine installation (m") Number of spindles or units of assembly in each apparatus Number of apparatus 60 Power consumption (KWH/IOO kg product) Comparative data of labor cost per 100 kg product As it is clearly shown in the above-mentioned table, the space required for machine installation, power consumption and labor cost can be remarkably reduced by utilization of the multiple twisting apparatus according to the present invention. Further, if the mode of arrangement of the two-for-one twisting assemblies along the front and back alignment is compared with .the mode of arrangement of the two-for-one twisting assemblies along a single alignment, it can be understood that the former mode of arrangement according to the present invention has also remarkable advantages compared to the latter mode of arrangement. That is, the latter mode of arrangement requires 1.48 times, 1.20 times, 1.4l times, the machine space, labor cost for doffing and donning and labor cost for inspection of the state of machine movement of that of the apparatus of the present invention, respectively.

What is claimed is:

1. A multiple twisting apparatus provided with at least one twisting unit comprising a first twisting device provided with at least two two-for-one twisting assemblies disposed in a sustantially upright condition, means 65 for doubling first-twisted yarns withdrawn from said two-for-one twisting assemblies, a secondring twisting assembly disposed below said first twisting device for imparting a second twist to a double yarn carried from I said doubling means,

a means for positively feeding said doubled yarn to said second twisting assembly, and

a plurality of yarn guides'for forming a yarn passage behind said first twisting device and for forming a yarn passage to said feeding means.

2. A multiple twisting apparatushaving at least one twisting unit, comprising a first twisting device provided with at least two twofor-one twisting assemblies disposed in a substantially upright condition, means for doubling first-twisted yarns withdrawn from said twofor-one twisting assemblies, a second ring twisting assembly disposed below said first twisting device for imparting a second twist to a double yarn carried from said doubling means, means for positively feeding said doubled yarn to said second twisting assembly, a plurality of yarn guides for forming yarn passage behind said first twisting device and for forming a yarn passage to said feeding means, and means for driving all twisting units so that in each twisting unit of said first twisting device and said second twisting assembly and said feeding means are driven synchronously during a period of starting and at a time of stopping the twistingoperation, said drive means comprising a main motor, a first belt drive means positively driven by said main motor by way of a first intermediate power transmission machanism, and a main shaft extended lengthwise of said apparatus below said apparatus and positively driven by said main motor by way of a second intermediate power transmission mechanism, a plurality of second belt drive means driven by said main shaft, a power transmission mechanism for driving said feeding mechanism connected to said first intermediate power transmission mechanism, said firstbelt drive means comprising an endless belt coupled to drive all of the two-forone twisting assemblies, each of said second belt drive means comprising an endless-belt coupled to drive a plurality of said ring twistibg assemblies as a group.

3. A multiple twisting apparatus according to claim Zfurther comprising a first means for controlling yarn tension along a passage between a delivery position of said two-for-one twisting assembly and said doubling means, and a second means for controlling yarn tension along said passage between said doubling means and said feeding means.

4. A multiple twisting apparatus according to claim 2 wherein each of said first twisting devices is provided with a clutch means for simultaneously engaging or disengaging each of said twisting devices to and from said endless belt of said first belt drive means independently of the other first twisting devices. I

5. A multiple twisting-apparatus according to claim 2'wherein said two-for-one twisting assemblies of a unit of said first twistingdevice are aligned along a line which is substantially perpendicular to a lengthwise direction of said apparatus.

6. A multiple twisting apparatus according to claim 2 wherein a plurality of first twisting devices are arranged along a lengthwise direction of said apparatus and a plurality of secondtwisting devices are arranged at corresponding positions below said first twisting devices respectively so that each twisting unit is composed of a first twisting device and a second twisting device.

ping the twisting operation.

10. A multiple twisting apparatus according to claim 3, wherein said first yarn tension control means is provided with a yarn tension detector and a limit switch connected to an actuating mechanism of said driving means, whereby said limit switch is actuated when said yarn tension detector detects a definite lowered condi:

tion of yarn tension to stop said driving means. 

1. A multiple twisting apparatus provided with at least one twisting unit comprising a first twisting device provided with at least two two-for-one twisting assemblies disposed in a sustantially upright condition, means for doubling first-twisted yarns withdrawn from said two-for-one twisting assemblies, a second ring twisting assembly disposed below said first twisting device for imparting a second twist to a double yarn carried from said doubling means, a means for positively feeding said doubled yarn to said second twisting assembly, and a plurality of yarn guides for forming a yarn passage behind said first twisting device and for forming a yarn passage to said feeding means.
 2. A multiple twisting apparAtus having at least one twisting unit, comprising a first twisting device provided with at least two two-for-one twisting assemblies disposed in a substantially upright condition, means for doubling first-twisted yarns withdrawn from said two-for-one twisting assemblies, a second ring twisting assembly disposed below said first twisting device for imparting a second twist to a double yarn carried from said doubling means, means for positively feeding said doubled yarn to said second twisting assembly, a plurality of yarn guides for forming yarn passage behind said first twisting device and for forming a yarn passage to said feeding means, and means for driving all twisting units so that in each twisting unit of said first twisting device and said second twisting assembly and said feeding means are driven synchronously during a period of starting and at a time of stopping the twisting operation, said drive means comprising a main motor, a first belt drive means positively driven by said main motor by way of a first intermediate power transmission machanism, and a main shaft extended lengthwise of said apparatus below said apparatus and positively driven by said main motor by way of a second intermediate power transmission mechanism, a plurality of second belt drive means driven by said main shaft, a power transmission mechanism for driving said feeding mechanism connected to said first intermediate power transmission mechanism, said first belt drive means comprising an endless belt coupled to drive all of the two-for-one twisting assemblies, each of said second belt drive means comprising an endless belt coupled to drive a plurality of said ring twistibg assemblies as a group.
 3. A multiple twisting apparatus according to claim 2 further comprising a first means for controlling yarn tension along a passage between a delivery position of said two-for-one twisting assembly and said doubling means, and a second means for controlling yarn tension along said passage between said doubling means and said feeding means.
 4. A multiple twisting apparatus according to claim 2 wherein each of said first twisting devices is provided with a clutch means for simultaneously engaging or disengaging each of said twisting devices to and from said endless belt of said first belt drive means independently of the other first twisting devices.
 5. A multiple twisting apparatus according to claim 2 wherein said two-for-one twisting assemblies of a unit of said first twisting device are aligned along a line which is substantially perpendicular to a lengthwise direction of said apparatus.
 6. A multiple twisting apparatus according to claim 2 wherein a plurality of first twisting devices are arranged along a lengthwise direction of said apparatus and a plurality of second twisting devices are arranged at corresponding positions below said first twisting devices respectively so that each twisting unit is composed of a first twisting device and a second twisting device.
 7. A multiple twisting apparatus according to claim 6, wherein said twisting units are disposed on a front side of said apparatus.
 8. A multiple twisting apparatus according to claim 6, wherein said twisting units are disposed on both sides of said apparatus.
 9. A multiple twisting apparatus according to claim 3, wherein said second yarn tension control means has a capability of reserving an excess length of yarn in a slackened condition which is created at a time of stopping the twisting operation.
 10. A multiple twisting apparatus according to claim 3, wherein said first yarn tension control means is provided with a yarn tension detector and a limit switch connected to an actuating mechanism of said driving means, whereby said limit switch is actuated when said yarn tension detector detects a definite lowered condition of yarn tension to stop said driving means. 